iio<S 



A TEXTBOOK OF THEORETICAL BOTANY 



225 

 210 

 195 

 180 

 165 

 •ISO 

 •135 

 •120 

 ■105 

 90 

 75 

 60 

 -45 

 -30 

 -15 



300 Flowers 



ISO 

 140 

 •130 



• 120 



• 110 

 ■100 

 90 

 •80 



70 

 ■60 

 •SO 

 -40 

 -30 

 -20 

 -10 



/I 



365 Flowers 



N 



1 — I — r 



I 2 3 4 5 6 7 8 9 10 II 12 

 Number of Nectaries 



-\ — I — I — I — I — I — I — I — I — r 



I 234S6789I0 

 Number of Carpels 



360 Flowers 



.'.00- 



280- 



260- 



240- 



220- 



200- 



180- 



160- 



140- 



120- 



100' 



80' 



60' 



X 



\ 



40- 



X 



X 20- 



— I — I — I — I — I — I — \ — r-¥- 



12 3 4 5 6 7 8 9 

 Number of Perianth Segments 



Fig. io8o. — Eranthis hienuilis. Graphs showing the extent of meristic variation. {After 



Scilisbtiry.) 



It is clear from these observations that 



fluctuating variations in the numbers of parts 



are continually appearing in certain species. 



On the other hand a particular meristic change 



may be a constant in some species and genera, 



in the sense that they are distinguished from 



related types either by a characteristic pleio- 



mery or meiomery of parts. Thus Megacarpaea 



(Fig. io8i) is peculiar among the Cruciferae in 



having ten or more stamens instead of six and 



Veronica is distinguished by the reduction ot 



its stamens to two instead of the five which 



make the full complement in Scrophulariaceae. 



No trace of the missing stamens remains in 



Veronica; it is an example of complete abor- 



FiG. io8i.— Pleiomeric androe- tion, or ablastv, without even rudiments being 

 cium '\r\. Megacarpaea {Cv\x- , i -v- i ,■ i 



ciferae). formed. Numerous other genera or the same 



